Locks have remained essentially unchanged in their basic concept for many years. Specifically, each lock in the prior art is usually manufactured to fit a certain key, and each lock may be operated only by that key, and never by a different key. In other words, the internal mechanism of the usual prior art lock is configured to fit a particular key only, and cannot be changed to match up with other keys unless the lock is taken apart and reset by a locksmith.
Attempts have been made in the prior art to provide locks which are more flexible than the usual type of prior art lock described in the preceding paragraph, and which may be set from time-to-time to operate with different keys. The present invention is concerned with such a lock, and a feature of the invention is the provision of an eminently simple lock which can be re-set at will to receive a different key, without the need for any special tools, and merely by turning the lock by the current key to a re-set position, withdrawing the current key, inserting the new key, and turning the lock back to its normal operating position by the new key.
The lock to be described also has an anti-pick feature in the form of a pick bar which engages the tumblers of the lock whenever the plug or carrier is turned from the reference position. The pick bar prevents movement of the tumblers unless the lock is in its reference position. This means that unless the proper key is inserted into the lock, initially to move the tumblers to their proper positions to permit the lock to be turned from the reference position and unlocked, no unlocking operation is possible; because the tumblers are immediately locked in their relative positions as set by the inserted key, upon an initial turning of the lock by the key from the reference position.
The lock of the invention finds particular utility for automotive purposes, as well as for use in conjunction with desks, file cabinets, and the like. However, it will become apparent as the description proceeds, that the lock has general utility wherever locks are used. It will also become apparent as the description proceeds, that the lock of the invention can be made simply, economically, and on a mass production basis, because each lock is exactly the same as all the others, and because each lock is composed of a minimum of operating components. The use of the lock of the present invention permits a person to purchase as many keys as desired for his lock, and to change the lock at will, without the need for any extraneous tools, so that it will operate with a different key, instead of the current key.
If the current key is lost, or stolen, the owner can use a duplicate of the current key to set the lock to a re-settable condition, and can re-set the lock to match an entirely different key, so that the original keys are no longer effective to operate the lock. Moreover, a person can set all his locks to fit a single key, so that but one key need be carried for home, car, office, and so on. In addition, all of the locks may be changed at any time to be operated by a different key, whenever desired, for security or other reasons. The lock of the present invention also has an advantage in that it can be constructed to have approximately the same size as the prior art cylinder locks, so that it can be easily mounted to replace existing locks, without the need for costly retrofit operations.